Real-time location systems are used to automatically identify and track the location of objects or people in real-time typically within a structure (e.g., hospital) or other enclosed area. Many such systems utilize wireless RTLS tags which are attached to the objects or worn by humans, and utilize fixed reference points which receive wireless signals from the RTLS tags to determine their current location. In typical operation, the RTLS tags (e.g., so-called “active” transponder tags) transmit a long-range signal (i.e., up to thousands of meters in accordance with recognized communications standards) at regular intervals, and location sensors receive and process the tag signals, and a location appliance collects and correlates the data for determining the current location of the object and/or person. In this way, RTLS typically allows for the positioning of multiple objects, usually in an indoor environment, in the range of tens of centimeters. RTLS is currently used in a variety of applications such as employee safety, workforce optimization, asset management, indoor navigation, and factory automation covering industries such as retail, construction, healthcare, manufacturing, education, and entertainment.
A robotic total station (also referred to as a “total station”) is an electronic/optical instrument used in modern surveying and construction, for example. The robotic total station is an electronic theodolite integrated with an electronic distance meter (EDM) to read slope distances from the instrument to a particular point and allows for a single person to effectively locate a target with assistance. That is, robotic total stations eliminate the need for multiple persons at the location of the total station to acquire a set of measurements. In one use of a robotic total station, the single user is at the target and sights the total station visually from the target and, upon visually locating the robotic total station, the user initiates an angular scanning sequence at the robotic total station to obtain more precise angular and distance measurements. The robotic total station automatically aligns itself with the target using, for example, servo motors that cause the robotic total station to be rotated towards the target. Once the robotic total station is aligned with the target (which is reflective in nature and may utilize one or more reflectors or prisms for such purpose), the angle and distance measurements can be taken and the position of the target may be determined in real-time or at some later time after a survey is completed, for example. In this way, a robotic total station typically allows for the precise positioning, usually in an outdoor environment, of a single object in the millimeter range.
As will be appreciated, while the aforementioned RTLS and RTS each have respective strengths in their ability to provide positioning information they also have respective limitations with respect to applicable operating environments (i.e., indoor vs. outdoor) and potential positioning targets (i.e., one at a time vs. multiple).
Therefore, a need exists for an improved technique for combining the use of a RTLS and RTS into a single, transparent positioning system.